Question
We recently moved and in the rear yard is a large mulberry tree.
It has a lot of 1/2 inch holes in the outer bark of the trunk and some boughs.
We asked our gardener to cut away the diseased boughs and give the tree a good pollarding. . This he did. The holes are still in parts of the trunk and boughs. Is this caused by a parasite that can be eradicated? Please advise. We live in central california.

Answer
Hi Charles,  This sounds like the redbay ambrosia beetle that bores in to the tree and lays eggs.  The beetle carries bacteria on its back legs etc. and as it bores into the tree it infects the tree and tissue and leads to overall decline eventually as the tree cannot repair itself fast enough naturally.  It sounds like the same beetle that gets into the Avocado trees in California and Florida.  I think the University is scrambling to figure out how to fix it as it is wiping out the Avocados down there.  You could try  Atomic Grow which is organic.  I sprayed it into stem holes on my erythrina cristagaldi and the new stems are coming out.  I was down to two branches and 1 leaf, I thought it was a gonner for sure but it is coming back to life.  I just cut off the dead branches back to green and sprayed into the hole.  You dilute one teaspoon to a quart of water, the only problem is you will want to use it on all your plants.  kathy